Back in January, we took a look at a couple rear panels for an unknown Sony smartphone. At the time, the theory was that this was the Xperia Z2, but the Z2 we actually saw Sony launch differed slightly from this design, notably in how the flash is positioned relative to the camera lens. In fact, while both the Z1 and the Z2 placed their flashes below the camera, this to-the-side arrangement was much more reminiscent of the Z1 Compact. This week, with the arrival of some new certification docs at the FCC, we might be starting to get to the bottom of this mystery, as rumors suggest that we’re looking at Sony’s work towards the release of a Z2 Compact.

The FCC paperwork describes Sony’s model SO-04F for NTT DoCoMo. With the Z1 and Z1f (Japan’s version of the Z1 Compact) models SO-01F and SO-02F, respectively, it doesn’t take a huge leap of faith to wonder if the Z2 and Z2 Compact might be 03F and 04F. The dimensions revealed for the SO-04F here also closely align with the Z1 Compact, coming in just a hair wider and taller. That’s led to speculation that Sony might be moving from the Z1 Compact’s 4.3-inch screen to something more like a 4.5-inch panel.

Mind you, this is a lot of guesswork, but we have to admit that it adds up to a compelling case. Really, the only thing that has us resisting this idea is that the Z1 Compact is still so very new itself, and it feels way too soon for a sequel – come summer, that might be a different story, so maybe Sony intends to sit on this guy for just a little while longer.